Research shows that people who think they have the most willpower are actually the most likely to lose control when tempted. For example, smokers who are the most optimistic about their ability to resist temptation are the most likely to relapse four months later, and overoptimistic dieters are the least likely to lose weight.

So how can we really increase willpower? What does science have to say?

When people start habitually exercising, even as infrequently as once a week, they start changing other, unrelated patterns in their lives, often unknowingly… “Exercise spills over,” said James Prochaska, a University of Rhode Island researcher. “There’s something about it that makes other good habits easier.”

Going to the gym is too much for you? Try food journaling. Just write down everything you eat, every day. It’s another powerful keystone habit.

The longer people have been awake, the more self-control problems happen. Most things go bad in the evening. Diets are broken at the evening snack, not at breakfast or in the middle of the morning. Impulsive crimes are mostly committed after midnight.

(To see the schedule that the most productive people use, click here.)

So your willpower is limited. What else can this tell us about the best way to use it?

Lower the activation energy for habits you want to adopt, and raise it for habits you want to avoid. The more we can lower or even eliminate the activation energy for our desired actions, the more we enhance our ability to jump-start positive change.

Unexpectedly, the best results came from the group working on posture. That tiresome old advice—“Sit up straight!”—was more useful than anyone had imagined. By overriding their habit of slouching, the students strengthened their willpower and did better at tasks that had nothing to do with posture.

We shouldn’t need to be told something so obvious, but cranky toddlers aren’t the only ones who resist much needed naps. Adults routinely shortchange themselves on sleep, and the result is less self-control.

…people who had told themselves “Not now, but later” were less troubled with visions of chocolate cake than the other two groups… Those in the postponement condition actually ate significantly less than those in the self-denial condition…

Anything other than just giving in helps strengthen your willpower muscle.

Study after study shows that self-criticism is consistently associated with less motivation and worse self-control. It is also one of the single biggest predictors of depression, which drains both “I will” power and “I want” power. In contrast, self-compassion— being supportive and kind to yourself, especially in the face of stress and failure— is associated with more motivation and better self-control.

People who cut themselves slack go on to keep trying — and end up succeeding.

…the more total self-control, the better the relationship fared. Multiple benefits were found for having mutually high self-control, including relationship satisfaction, forgiveness, secure attachment, accommodation, healthy and committed styles of loving, smooth daily interactions, absence of conflict, and absence of feeling rejected.

Willpower is one of the first steps in improving any area of life — and it’s good to know that self-control isn’t selfish.